The invention relates to apparatus for grinding cylindrical or conical primary crown castings used in the replacement of teeth which are provided with retaining pins resulting from the casting channels and extending from the top side of the castings in axial alignment with the centerlines of the castings. Primary crown castings used in the replacement of teeth and adapted to be mounted on appropriate anchoring members need to be ground, after casting, in such a manner that their side surfaces are parallel to their axis (in 0.degree. position) for telescopic or cylindrical crowns and for conical crowns in such a manner that they extend at an angle of between 0.degree. and 12.degree. with respect to the axis. In order to facilitate the grinding of such crown castings it has been necessary to provide a handling arrangement which not only made the handling of the crown castings possible but which also required identification of the 0.degree. position, that is, the axis or centerline of the casting. In accordance with a newer method the casting liquid supply channel was so arranged as to coincide with the crown centerline or axis so that the expensive and timeconsuming determination of the axis of the casting body was no longer necessary. The pin formed by the material supply channel for the casting could be used this way as a support or retaining member. The side walls of the casting are then worked utilizing the casting material pin as a reference point for grinding the side surfaces either parallel to the centerline (0.degree. ) or at a predetermined angle relative to the centerline.